Think ISR just stands for industry standard rails. My PR had a little slop in it when starting stopping, even when adjusted properly. My Demco Hitchiker does the same. The only thing that prevents chucking is at the pinbox; Morryde and 5th Airborne vome to mind.
--2005 Ford F350 Lariat Crewcab 6.0, 4x4, 3.73 rear
--2016 Montana 3711FL, 40'
--2014 Wildcat 327CK, 38' SOLD